Various heating devices are known and are used in the automotive industry. Examples of such heating devices include seat heaters that are used in many vehicles to improve the comfort of passengers riding in the vehicle. Some of these known seat heaters include a flexible heating device that is used to maintain the flexural characteristics of the seat. Examples of such heaters can be found in U.S. Pat. Nos. 6,884,965 and 7,053,344, both commonly owned by the applicant and incorporated herein by reference. These heaters have proven satisfactory and provide additional benefits including increased heating capacity, uniformity of heating, and protection against contact with liquid spills, among other benefits.
Recently, occupant sensors have been incorporated into automobile seats. These occupant sensors have been used to provide a reminder signal that if a seat is occupied but the associated seatbelt is not being employed, the occupant is alerted to fasten the seatbelt. Occupant sensors have also been used with vehicle air bags. In these applications, depending on the data collected by the occupant sensor, the air bag may be activated so that it is ready for deployment if needed. More specifically, as the occupant sensor detects the weight of the passenger sitting on the seat, a processor calculates the weight or other parameters and sends a signal to a controller to perform a certain action, such as activation of the air bag for deployment. In another embodiment, depending on the weight of the occupant, the signal to the controller may be to reduce the amount of force in which the air bag will release. In North America, for example, federal regulations require occupant sensor to have the ability to detect size and weight of an occupant.
Presently, automotive seat heaters and occupant sensors exist as separate components within a seat and utilize different technologies. For example, seat heaters typically include fabric based, wire wound elements, or carbon fiber elements. Occupant sensors on the other hand are often plastic sheet based, screen printed, polymer thick film (PTF). Each of the two technologies works well alone but when combined each can cause difficulties to the operation of the other's systems. For example, the heater wires and carbon fiber can interfere with the sensing capabilities of the occupant sensors, causing false or incorrect readings due to heat and varying pressure points. As a result, many known vehicle seats having an occupant sensor do not include the seat heater option, or the seat heater is installed below the occupant sensor which severely limits the seat heater's performance. Consequently, there exists a need in the automotive industry for a combination seat heater and occupant sensor device. The present invention addresses these and other known drawbacks with existing seat heater and occupant sensor devices.